Process for the mechanical trimming of pieces



March s, 1938. L. SAIVES 2,110,530

PROCESS FORTHE MECHANICAL TRIMMING OF PIECES Filed June 10, 1936' al Pe Patented Mar. 8, 1938 d PROCESS FOR THE MECHANICAL TRIM- MING or PIECES Leon Saives, Billancourt, France, assignor, to Louis Renault, Blllancourt,; France Application June 10, 1936, Serial No. 84,586 In. France August 8, 1935 2 Claims. ((31. 90-11) The present invention relates to a process for cast iron box I of suitable size having at itsthe mechanical trimming of pieces of any kind by the reproducing machine, and is chiefly applicable to the trimming of pieces for which there 5 is a risk of deformation before or after the trimming, for instance in the trimming of airplane propellers consisting of a light alloy.

, The airplane propellers which consist of a light alloy composed largely of aluminium or magnesium, comprise two, three or four blades, and

the manufacture of each'of such blades includes the following operations.

l. A forging which is followed by a pressing;

operation adaptedto give to the'blade a shape which comes as near as possible to its definite shape. 7

2. A treatment by which themetal is-given the proper hardness and strength. I 3. A trimming for the external shape of the blades.

Thisdatter operation is performedat the present time either entirely by hand by the. use of 7 portable milling cutters or grinders, or by hand for the first face and by the reproducing machine for the second face. For the trimming of the first face by the reproducing machine, it is necessary to strongly secure the blade to a support by means of clamps, but without any distortion. The presentinvention permits to obtain this result, and it consists in \using as a support, a box containing freshly prepared plaster uUOn which the piece to be trimmed, such as a blade.

is lowered and is placed exactly in the position which the said piece is to occupy during the trimming. The bottom of the said box is planed smooth in orderthat it may be mounted on the tabl of the reproducing machine.

Inge accompanying dra The device shown in the drawing comprises a g shows by way of ex ple an embodiment o the invention which '40 serves for the trimming of propeller blades.

lower part a contact face 2 which is planed smooth in order that it may be mounted on the reproducing table. To secure the blade to be trimmed to the said support, freshly prepared plaster 3 is placed in the said box, and the blade 4 is loweredlnto the exact position which it is to occupy during the trimming of its upper face. When the plaster 3 has sufiloiently set, the blade is firmly held in place by clamps 5- 8'--1--8 which-are pressed against the-blade by screws FIB-l l-.-l2.

The operator begins by trimmingthe part between the clamps 5 and 6, and then removes the clamp 6 for the trimming at this point, after which he puts the clamp in place and then carries out 'the trimming between the clamps 8 and l, and so on'. When the upper face has been trimmed, the blade is reversed upon a device provided with a template, as in known practice. and the operatorthen trims the other face.

By operating in the manner above indicated, it is" possible to effect the mechanical trimming of the first face of the blade, without any risk of deformation'of this face after the trimming operation.

f I claim:-- v

1. A process for mechanically trimming pieces of'work having relatively large irregular fiat surfaces to be machined, consisting in placing freshlyprepared plaster in abommounting the piece of workon the-plasterv so that the latter conforms to the lowersurface of the piece of work and is substantially coextensive therewith and so that the upper surface to betrim'med is ex- 35 posed, permitting the plaster to set, removably and independently clamping the piece of work to the plaster at different points on the face to be trimmed and then finishing the upper surface of the piece of work. 4 40 2. The-application of the process claimed in claim 1 to the mechanical trimming of the first face of a propeller blade,-

' LEON SAIVES. 

